We allow the ust_mutex lock to be nested within the same thread using the ust_mutex_nest counter. When calling ust_lock(), ust_lock_nocheck() or ust_unlock() twice or more in the same thread would result in an error message being thrown.
This error message always appear when an application calls fork(3) (with liblttng-ust-fork preloaded), the thread would lock before the fork(3) in ust_before_fork() and the child would lock again during lttng_after_fork_child(). Signed-off-by: Gabriel-Andrew Pollo-Guilbert <gabriel.pollo-guilb...@efficios.com> --- liblttng-ust/lttng-ust-comm.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/liblttng-ust/lttng-ust-comm.c b/liblttng-ust/lttng-ust-comm.c index 61dbb41b..a6449bbc 100644 --- a/liblttng-ust/lttng-ust-comm.c +++ b/liblttng-ust/lttng-ust-comm.c @@ -135,7 +135,9 @@ int ust_lock(void) ERR("pthread_setcancelstate: %s", strerror(ret)); } if (oldstate != PTHREAD_CANCEL_ENABLE) { - ERR("pthread_setcancelstate: unexpected oldstate"); + if (!URCU_TLS(ust_mutex_nest)) { + ERR("pthread_setcancelstate: unexpected oldstate"); + } } sigfillset(&sig_all_blocked); ret = pthread_sigmask(SIG_SETMASK, &sig_all_blocked, &orig_mask); @@ -171,7 +173,9 @@ void ust_lock_nocheck(void) ERR("pthread_setcancelstate: %s", strerror(ret)); } if (oldstate != PTHREAD_CANCEL_ENABLE) { - ERR("pthread_setcancelstate: unexpected oldstate"); + if (!URCU_TLS(ust_mutex_nest)) { + ERR("pthread_setcancelstate: unexpected oldstate"); + } } sigfillset(&sig_all_blocked); ret = pthread_sigmask(SIG_SETMASK, &sig_all_blocked, &orig_mask); @@ -210,7 +214,9 @@ void ust_unlock(void) ERR("pthread_setcancelstate: %s", strerror(ret)); } if (oldstate != PTHREAD_CANCEL_DISABLE) { - ERR("pthread_setcancelstate: unexpected oldstate"); + if (URCU_TLS(ust_mutex_nest)) { + ERR("pthread_setcancelstate: unexpected oldstate"); + } } } -- 2.21.0 _______________________________________________ lttng-dev mailing list lttng-dev@lists.lttng.org https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev